A 1‐year prospective analysis of injuries in amateur and elite fistball

The purpose of this study was to examine the incidence and mechanisms of acute injuries in the sport of fistball. No scientific studies on injury characteristics have yet been conducted in this traditional sport game. The study was conducted prospectively over the course of 12 months. During a total of 40.308 h of sport‐specific exposure, 240 players reported 492 injuries, representing an overall injury rate of 12.2 injuries/1000 h of exposure. Most injuries were classified as bagatelle injuries (67.8%). The majority of the injuries were located in the knee (23.5%) followed by the elbow (11.9%) and the hip (11.5%). Ankle injuries resulted in the longest impairment from sports participation. The most common types of injury were abrasions (38.2%), contusions (21.1%), distortions (7.5%) and muscle strains (6.9%). Wrong or insufficient equipment (15.0%) was the most commonly mentioned causes of injury. The data indicate that the injury risk in fistball is rather high; however, the sport should not be considered a high‐risk sport because most of the injuries are slight and do not prevent the players from training or competition. Injury prevention strategies should include the development of fistball‐specific protective equipment with focus on the knee and elbow joint.     

Development of aerobic and anaerobic power in adolescent rowers: a 5‐year follow‐up study

We aimed to determine whether the physical and physiological superiority of early‐maturing rowing athletes, observed at ages 12–13 years, over that of their late‐maturing counterparts observed at the same ages, still persists at 17–18 years of age, when all adolescent athletes are expected to have completed pubertal development. We hypothesized that this superiority of early maturers would not be observed at reassessment, as late maturers would have likely “caught up” with their early‐maturing peers. Twenty‐one male rowers were assessed at age 12.8 ± 0.5 years and again at 17.5 ± 0.5 years (mean ± SD). They were divided into groups of early‐maturing and late‐maturing rowing athletes based on Tanner's sexual maturity ratings. A two‐way repeated‐measures MANOVA followed by a series of ANOVAs with one within‐subject factor (time) and one between‐subject factor (group) indicated significant (P≤0.003) within‐subject and between‐subjects main effects for lean body mass (LBM), maximal oxygen uptake (), and mean power (MP). The group × time interaction effects were significant for LBM (P=0.003), (P=0.004), but not for MP (P=0.171). Over 5 years, early‐maturers' advantage dwindled in terms of LBM (+38% to +9%), (+47% to +9%), and MP (+76% to +15%); however, these differences may still be considered practically relevant. The proposed hypothesis was not supported.     

Injury risk factors in junior tennis players: a prospective 2‐year study

The aim was to investigate injury risk factors in junior tennis players. Fifty‐five players, 35 boys and 20 girls, answered a questionnaire about training habits, time of exposure, previous injuries and equipment factors. A battery of clinical tests and functional performance tests were also carried out. All tennis‐related injuries that occurred during a 2‐year period were identified and recorded. An injury was defined as an injury if it was impossible to participate in regular tennis training or playing matches during at least one occasion, a time loss injury. Potential injury risk factors were tested in a forward stepwise logistic regression model for injury. Thirty‐nine players sustained totally 100 new and recurrent injuries. Injuries to the lower extremity were the most common ones (51%) followed by the upper extremity (24%) and the trunk (24%). Injured players performed more singles per week (P<0.0001) and played more tennis hours per year (P=0.016) than the uninjured players. Playing tennis more than 6 h/week was found to be a risk factor for back pain. A previous injury regardless of location was identified as an injury risk factor, and a previous injury to the back was a risk factor for back pain.     

Gradual increase in the risk of match injury in Norwegian male professional football: A 6‐year prospective study

The aim of this study was to monitor injury incidence and pattern in Norwegian male professional football over six consecutive seasons and compare the risk of injury between the preseason and competitive season. All time loss injuries were recorded by the medical staff of each club. In total, 2365 injuries were recorded. The incidence of acute injuries was 15.9/1000 match hours [95% confidence interval (CI): 14.9–16.8], 1.9/1000 training hours (95% CI: 1.7–2.0), and 1.4 (95% CI: 1.3–1.5) overuse injuries/1000 h. A linear regression model found an annual increase of 1.06 acute match injuries/1000 h (95% CI: 0.40–1.73), corresponding to a total increase of 49% during the 6‐year study period. When accounting for interteam variation and clustering effects using a general estimating equation model, the increase in injury incidence was 0.92 (95% CI: ?0.11–1.95, P = 0.083). No difference in the risk of acute match injuries (rate ratio (RR): 0.86, 95% CI: 0.73–1.01), acute training injuries (RR: 1.16, 95% CI: 0.99–1.36), or overuse injuries (RR: 1.04, 95% CI: 0.89–1.21) was observed between the preseason and competitive season. In conclusion, the overall risk of acute match injuries in Norwegian male professional football increased by 49% during the study period, although this increase was not fully consistent across teams. We detected no change in the risk of training and overuse injuries or any difference between the preseason and competitive season.     

Risk factors for patellar tendinopathy in volleyball and basketball players: A survey‐based prospective cohort study

Patellar tendinopathy (PT) is a common overuse injury of the patellar tendon in jumping athletes. In a recent large cross‐sectional study from 2008 several factors were identified that may be associated with the etiology of PT. However, because of the study design no conclusions could be drawn about causal relations. The primary aim of the current study is to investigate whether the factors identified in the previous 2008 study can also be prospectively recognized as predictors of symptomatic PT in 2011. Nine hundred twenty‐six Dutch elite and non‐elite basketball and volleyball players from the previous study were invited again to complete an online survey about knee complaints and risk factors for PT in 2011. The logistic regression included 385 athletes of which 51 (13%) developed PT since 2008. Male gender [odds ratio (OR) 2.0, 95% confidence interval (CI) 1.1–3.5] was found to be a risk factor for developing PT. No sports‐related variables could be identified to increase the risk of developing PT, but some evidence was found for performing heavy physically demanding work, like being a nurse or a physical education teacher (OR 2.3, 95% CI 0.9–6.3). These findings indicate that, when considering preventive measures, it is important to take into account the total tendon load.     

Functional and muscle morphometric effects of ACL reconstruction. A prospective CT study with 1 year follow‐up

Computed tomography (CT) was used to explore if changes in muscle cross‐sectional area and quality after anterior cruciate ligament (ACL) injury and reconstruction would be related to knee function. Fourteen females and 23 males (16–54 years) underwent clinical tests, subjective questionnaires, and CT 1 week before and 1 year after ACL surgery with semitendinosus‐gracilis (STG) graft and rehabilitation. Postoperatively, knee laxity was decreased and functional knee measures and subjective patient scores improved. The most obvious remaining deficit was the quadriceps atrophy, which was significantly larger if the right leg was injured. Right‐leg injury also tended to cause larger compensatory hypertrophy of the combined knee flexor and tibial internal rotator muscles (preoperatively). The quadriceps atrophy was significantly correlated with the scores and functional tests, the latter also being related to the remaining size of the gracilis muscle. Biceps femoris hypertrophy and, in males only, semimembranosus hypertrophy was observed following the ACL reconstruction. The lack of semimembranosus hypertrophy in the women could, via tibial internal rotation torque deficit, contribute to the less favorable functional and subjective outcome recorded for the women. The results indicate that the quadriceps, the combined knee flexor/tibial internal rotator muscles, side of ACL injury, and sex are important to consider in rehabilitation after STG graft.     

Acute hamstring strain injury in track‐and‐field athletes: A 3‐year observational study at the Penn Relay Carnival

This study aimed to observe the incidence rates of hamstring strain injuries (HSIs) across different competition levels and ages during the Penn Relays Carnival. Over a 3‐year period, all injuries treated by the medical staff were recorded. The type of injury, anatomic location, event in which the injury occurred, competition level, and demographic data were documented. Absolute and relative HSI (per 1000 participants) were determined, and odds ratios (ORs) were calculated between sexes, competition levels, and events. Throughout the study period 48 473 athletes registered to participate in the Penn Relays Carnival, with 118 HSIs treated by the medical team. High school girls displayed lesser risk of HSI than high school boys (OR = 0.55, P = 0.021), and masters athletes were more likely than high school‐ (OR = 4.26, P < 0.001) and college‐level (OR = 3.55, P = 0.001) athletes to suffer HSI. The 4 × 400‐m relay displayed a greater likelihood of HSI compared with the 4 × 100‐m relay (OR = 1.77, P = 0.008). High school boys and masters‐level athletes are most likely to suffer HSI, and there is higher risk in 400‐m events compared with 100‐m events.     

Fundamental movement skills and physical fitness as predictors of physical activity: A 6‐year follow‐up study

The purpose of this study was to examine the extent to which fundamental movement skills and physical fitness scores assessed in early adolescence predict self‐reported physical activity assessed 6 years later. The sample comprised 333 (200 girls, 133 boys; M age = 12.41) students. The effects of previous physical activity, sex, and body mass index (BMI) were controlled in the main analyses. Adolescents’ fundamental movement skills, physical fitness, self‐report physical activity, and BMI were collected at baseline, and their self‐report energy expenditure (metabolic equivalents: METs) and intensity of physical activity were collected using the International Physical Activity Questionnaire 6 years later. Results showed that fundamental movement skills predicted METs, light, moderate, and vigorous intensity physical activity levels, whereas fitness predicted METs, moderate, and vigorous physical activity levels. Hierarchical regression analyses also showed that after controlling for previous levels of physical activity, sex, and BMI, the size of the effect of fundamental movement skills and physical fitness on energy expenditure and physical activity intensity was moderate (R² change between 0.06 and 0.15), with the effect being stronger for high intensity physical activity.     

Back injuries in a cohort of schoolchildren aged 6–12: A 2.5‐year prospective study

The aims of this prospective school cohort study were to describe the epidemiology of diagnosed back pain in childhood, classified as either nontraumatic or traumatic back injury, and to estimate the association with physical activity in different settings. Over 2.5 years, 1240 children aged 6–12 years were surveyed weekly using mobile text messages to ask about the presence or absence of back pain. Pain was clinically diagnosed and injuries were classified using the International Classification of Diseases version 10. Physical activity data were obtained from text messages and accelerometers. Of the 315 back injuries diagnosed, 186 injuries were nontraumatic and 129 were traumatic. The incidence rate ratio was 1.5 for a nontraumatic back injury compared with a traumatic injury. The overall estimated back injury incidence rate was 0.20 per 1000 physical activity units (95% confidence interval 0.18–0.23). The back injury incidence rates were higher for sports when exposure per 1000 physical activity units was taken into consideration and especially children horse‐riding had a 40 times higher risk of sustaining a traumatic back injury compared to the risk during non‐organized leisure time physical activity. However, the reasonably low injury incidence rates support the recommendations of children continuously being physically active.     

Musculoskeletal extremity injuries in a cohort of schoolchildren aged 6–12: A 2.5‐year prospective study

The objectives of this prospective school cohort study were to describe the epidemiology of diagnosed musculoskeletal extremity injuries and to estimate the injury incidence rates in relation to different settings, different body regions and injury types. In all, 1259 schoolchildren, aged 6–12, were surveyed weekly during 2.5 years using a new method of automated mobile phone text messaging asking questions on the presence of any musculoskeletal problems. All injuries were clinically diagnosed. Physical activity was measured from text messaging and accelerometers. A total number of 1229 injuries were diagnosed; 180 injuries in the upper extremity and 1049 in the lower extremity, with an overall rate of 1.59 injuries per 1000 physical activity units [95% confidence interval (CI) 1.50–1.68]. Upper extremities accounted for a rate of 0.23 (95% CI 0.20–0.27) and lower extremities accounted for 1.36 (95% CI 1.27–1.44). This study has added a wide overall perspective to the area concerning incidence and incidence rates of musculoskeletal extremity injuries in schoolchildren aged 6–12 years, including severe and less severe, traumatic, and overuse injuries. The understanding of injury epidemiology in children is fundamental to the acknowledgement and insurance of the appropriate prevention and treatment.     

Change in physical activity and health‐related quality of life in old age—A 10‐year follow‐up study

The aim of the study was to examine the association between change in leisure‐time physical activity (LTPA) and change in health‐related quality of life (HRQoL) and symptoms of depression during a 10‐year follow‐up. This prospective study included 1036 men and women (mean age at baseline = 61.2 years) from the Helsinki Birth Cohort Study. Leisure‐time physical activity was measured with a questionnaire, HRQoL with SF36 and depression symptoms with Beck's depression inventory (BDI). The association between the change in LTPA and change in HRQoL and BDI were investigated with sex‐stratified general linear models adjusted for age, smoking, educational attainment, comorbidity score, and baseline value of outcomes. One standard deviation (SD) increase in LTPA was associated with increase in physical summary component of HRQoL in women (B = 0.7 unit, 95% CI = 0.1‐1.3, P = 0.032) and in men (B = 0.8 unit, 95% CI = 0.2‐1.5, P = 0.014). In women, the 1SD increase in LTPA was also associated with an increase in mental summary component score (B = 1.0, 95% CI = 0.3‐1.7, P = 0.005) and a reduction in depressive symptoms (B = ?0.7, 95% CI = ?1.1 to ?0.2, P = 0.003). In conclusion, increase in the volume of LTPA over a 10‐year period in late adulthood was associated with improved HRQoL in both men and women, and also diminished depressive symptoms in women. The findings support the promotion of physical activity in later years to enhance HRQoL and mental well‐being.     

High injury incidence in TeamGym competition: a prospective cohort study

TeamGym is a relative new form of gymnastics originating from Scandinavia. Little is known regarding injury incidence and injury types. The aim of this study was to examine the injury pattern and incidence in Norwegian TeamGym competition. The study is a prospective cohort, with one 10-month season [17 competitions, n=8418 athlete-exposures (A-Es), a total of 1134 h of exposure]. Injury pattern, incidence and exposure during competition were collected using an injury registration form. During the competitions, 115 injuries were reported including 49 (43%) acute injuries, 58 (50%) exacerbations and eight (7%) re-injuries. The injury incidence was 50.3/1000 h or 6.8/1000 A-Es. Ankle injuries accounted for 25.6/1000 h. A total number of 30 time-loss injuries were found, giving 27 injuries per 1000 h. The high proportion of exacerbations shows that the gymnasts competed even if they had not recovered fully from previous overuse or acute injuries. A higher injury rate was observed in competition than during the pre-competition apparatus warm-up. Eighty-four per cent of the injuries occurred in the landing phase of the gymnastic skill. No sex differences were observed. The injury rate in Norwegian TeamGym competition is high, in particular for ankle injuries.     

Neuromuscular training reduces lower limb injuries in elite female basketball players. A cluster randomized controlled trial

The study was a two‐armed, parallel group, cluster randomized controlled trial in which 15 teams (160 players) were assigned to either an experimental group (EG , 8 teams n = 86), which warmed‐up with bodyweight neuromuscular exercises, or a control group (CG , 7 teams, n = 74) that performed standard tactical‐technical exercises before training. All injuries during the 2015‐2016 regular season were counted. Epidemiologic incidence proportion and incidence rate were also calculated. Countermovement jump (CMJ ) and composite Y‐Excursion Balance test (YBT ) were used to assess lower limb strength and postural control. A total of 111 injuries were recorded. Chi‐square test detected statistically significant differences between EG and CG (32 vs 79, P  = .006). Significant differences in the injuries sustained in the EG (21 vs 11, P  = .024) and CG (52 vs 27, P  = .0001) during training and matches, respectively, were observed. Significant differences in post‐intervention injuries were observed between in EG and CG during training (21 vs 52, P  < .0001) and matches (11 vs 27, P  = .006). Significant differences in epidemiologic incidence (0.37 vs 1.07, P  = .023) and incidence rate (1.66 vs 4.69, P  = .012) between the EG and the CG were found. Significant improvement in CMJ (+9.4%, P  < .0001; d  = 1.2) and composite YBT (right: +4.4%, P  = .001, d  = 1.0; left: +3.0%, P  = .003; d  = 0.8) for the EG was noted. Significant differences in post‐intervention CMJ (+5.9%, P  = .004) and composite YBT scores (right, +3.7%, P  = .012; left, +2.3%, P  = .007) between the EG and the CG were observed. Including bodyweight neuromuscular training into warm‐up routines reduced the incidence of serious lower limb injuries in elite female basketball players.     

A one‐season prospective study of injuries and illness in elite junior tennis

The objective of this study was to estimate the incidence and prevalence of injury and illness among elite junior tennis players. A cohort of 73 players (11–14 years) in the 2012–2013 Dutch national high‐performance program was followed for 32 weeks; all participants completed the study. The OSTRC Questionnaire on Health Problems was used to record self‐reported injuries and illnesses and to record training and match exposure. Main outcome measures were average prevalence of overuse injury and illness and incidence density of acute injury. On average, players practiced 9.1 h/week (SD 0.6; range 2.3–12.0) and had 2.2 h of match play (SD 0.6; range 2.3–12.0). During the course of the study, 67 players reported a total of 187 health problems. The average weekly prevalence of all health problems was 21.3% (95% CI: 19.2–22.9), of which 12.1% (95% CI: 10.9–13.3) constituted overuse injuries and 5.8% (95% CI: 4.6–6.9) illnesses. The incidence of acute injuries was 1.2/1000 h of tennis play (95% CI: 0.7–1.7). The high occurrence of overuse injuries among elite junior tennis players suggests that an early focus on preventative measures is warranted, with a particular focus on the monitoring and management of workload.     

Injuries in Swedish elite football--a prospective study on injury definitions, risk for injury and injury pattern during 2001

The purpose of this study was to study the risk for injury and injury pattern in Swedish male elite football and to compare two different injury definitions. A prospective cohort study was conducted during 2001 on all 14 teams (310 players) in the Swedish top division. Injuries and individual exposure were recorded. Injury was defined as time-lost injury (715 injuries) and for comparison as tissue injury (765 injuries). No significant difference in the risk for injury between tissue injuries and time-lost injuries was found during matches (27.2 vs. 25.9 injuries per 1000 match hours, P=0.66) or training sessions (5.7 vs. 5.2 injuries per 1000 training hours, P=0.65). The risk for injury during training was significantly higher during the pre-season compared with the competitive season (P=0.01). Thigh strain was the single most common injury (14%). Knee sprain was the most common major injury (absence >4 weeks). Overuse injuries and re-injuries were frequent and constituted 37% and 22% of all injuries. Re-injuries caused significantly longer absence than their corresponding initial injuries (P=0.02). The risk for re-injury (P=0.02) and overuse injury (P<0.01) was significantly higher during the pre-season compared with the competitive season.     

A prospective study of injuries in licensed floorball players

Injuries occuring among 457 licensed floorball players in teh Swedish National League were analysed prospectively during the season from 1993 to 1994. Fifty-one (11%) players sustained 58 injuries. The majority (76%) of the injuries were due to trauma mostly during the game (55%). Twenty-three (52%) of the traumatic injuries were caused by an opponent or a stick. Ankle sprain (35%) was the most common diagnosis. Injury severity classified with regard to time of absence from sport participation were similarly distributed for minor (36%), moderate (29%) and major (35%) injuries. The total rate of injury was 2.5 per 1000 hours for female and 2.6 for male players. Although this rate is lower than for contact sports like soccer and ice-hockey, we feel that further investigation of floorball injuries and improvement of protection devices would be valuable.     

How stressors are dynamically appraised within a team during a game: An exploratory study in basketball

Little is known about how team sport athletes individually and collectively experience sources of stress during competitive sport encounters. This study aimed to examine the nature of the stressors team sport athletes appraised during games at individual and team levels, as well as their degree of synchronization during an unfolding game. Through individual self‐confrontation interviews, the activities of nine basketball players of the same team were examined in detail. The results revealed that 12 categories of stressors were reported, and categorized into two larger units reflecting stressors perceived as affecting (a) “the team functioning as a whole” and (b) “a player's own functioning”. Thus, the nature and degree of similarity of the game‐specific stressors experienced by basketball players within a single team were identified during a game. In addition, the findings showed six different patterns of synchronizations of team members’ stressors, as well as their changes over the course of the game. They provided support for the synchronized appraisal and experience of stressors within a team during a game. By adopting an interpersonal perspective and examining the temporal interplay in team members’ activities, this study shed light on stress within teams.     

The Swedish physical activity and fitness cohort born in 1958 – dropout analysis and overview at 36‐year follow‐up

The main aim of the Swedish physical activity and fitness cohort study (SPAF‐1958) was to describe physical fitness, physical activity, health, and lifestyle across part of the lifespan, and to assess the influences on these factors from the environment, personal factors, and genetics. There is inevitable dropout from longitudinal studies, and it may be systematic. The aim of this first paper of the second follow‐up of SPAF‐1958 was to provide a dropout analysis to consider to what extent the participants, at 52 years of age, remain a representative sample of the original adolescent study population. Additional aims were to provide an overview of the study protocol and the ongoing study population. Ongoing study participants in SPAF born in 1958 were, at the second follow‐up at the age of 52, still representative of the study cohort in terms of sex, adolescent geographical area, upper secondary school program, adolescent body composition, muscular strength, and muscular endurance. However, a higher physical activity and, among women, a higher aerobic capacity in adolescence decreased the risk for dropout. It is important when interpreting results from longitudinal studies to adjust for the systematic dropout that could bias the conclusions drawn from the results.     

The prevalence and severity of health problems in youth elite sports: A 6‐month prospective cohort study of 320 athletes

Little is known regarding the overall health of youth elite athletes. Our aim was to describe the prevalence and severity of health problems in a cohort of youth elite athletes representing a variety of endurance, team, and technical sports. Elite sport athletes (N = 260, 16.2 years) from different Sport Academy High Schools in Norway, and a group of their teammates (N = 60, 16.4 years) attending regular high schools, were included in the study. The Oslo Sports Trauma Research Centre (OSTRC ) questionnaire on health problems was used to self‐report injuries and illnesses for 26 weeks. At any given time, an average of 43% [95% CI : 37%‐49%] of the elite sport athletes had some form of health problem and 25% [20%‐31%] had substantial health problems. The prevalence of health problems was similar between the elite team sport athletes and their teammates, except for substantial injuries (22% [16%‐30%] vs 10% [5%‐20%]). Endurance sport athletes reported more illnesses (23% [15%‐35%]) than technical and team sport athletes (10% [5%‐20%] and 8% [4%‐14%]). In contrast, technical and team sport athletes reported more injuries (36% [95% CI : 25‐48] and 37% [95% CI 29‐45]) compared to endurance sport athletes (15% [8%‐25%]). The total impact of health problems was roughly split in thirds between overuse injuries (37%), acute injuries (34%), and illnesses (30%). This is the first prospective study to present self‐reported injury and illness data in a large heterogeneous group of youth elite athletes, documenting a substantial impact of both injuries and illnesses on the health of this population.     

The interaction between constituent year and within‐1‐year effects in elite German youth basketball

The current state of research on relative age effects in basketball shows an uneven picture. These mixed results might be caused by the interaction of constituent year and within‐year effects. Our aim was to examine constituent and within‐1‐year effects in elite German youth basketball. The sample (n = 4400) included players competing in the JBBL (Under‐16 first division) and the NBBL (Under‐19 first division) from 2011/2012 until 2013/2014. A multi‐way frequency analysis revealed an interaction of constituent year effects and within‐1‐year effects for the JBBL, χ²(6, 2590) = 12.76, P < 0.05. NBBL data showed significant constituent year effects, χ²(2, n = 1810) = 25.32, P < 0.01, and within‐1‐year effects for all three age bands but no interaction. The interaction between constituent year and within‐1‐year effects in the JBBL showed reduced within‐1‐year effects with increasing age. Once players enter the system in the JBBL, relatively younger players seem less likely to drop out of the system. Results offer new insight regarding how the regulations of this talent development system may influence athletes' opportunities to enter the system and their likelihood of staying at the highest levels of competition.